Conventionally, there have been known game devices (video game devices, etc.) in which players control a mock gun and shoot a target or the like displayed on a screen. One type of such game devices uses a cathode ray tube display and this is described for example: when the player points the mock gun at the screen and pulls the trigger, the game devices cause the screen to flash (display a flashing image) only for an instant. The flashing light is then detected by a sensor provided on the muzzle or other part of the mock gun, and the position of the gun sight on the screen (the position aimed at by the player) is obtained based on the timing in the raster scan at the time of this detection.
The recently disclosed techniques of game devices have achieved enhanced reality of shooting, not only by displaying a target, etc. on a main screen, such as a display, but also by displaying a sub screen on a sighting device (a scope for taking a sight) provided on the mock gun (see, for example, Patent Literature 1).    Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2001-87544 (pp. 4-11, FIG. 1).